South Australia and Victoria are braced for near-record temperatures and the spread of bushfires as heatwave conditions persist in south-eastern Australia today.

The states are bearing the brunt of scorching heat and high-fire-danger conditions, while New South Wales and the ACT are also expecting near-record temperatures.

Adelaide, which the Bureau of Meteorology (BoM) confirmed as the hottest city in the world soon after midday, is expected to experience one of its hottest days on record, with a forecast top of 46 degrees Celsius[114.8ºF].

The BOM has confirmed #Adelaide is currently the hottest city in the world at 42.4°C[108.3ºF]. A maximum temp of 46°C is forecast #heatwave — ABC News 24 (@ABCNews24) January 16, 2014

However, much of the fire danger is centred on SA's west coast, where crews are being pushed to the limit as they continue to battle about 15 blazes.

In Victoria, electrical storms overnight sparked blazes across the centre of the state, with one woman hospitalised after being struck by lightning.

Melbourne, meantime, is facing its longest run of 40C[104ºF] days since 1908. It did not drop below 27.2C[81ºF] in the Victorian capital overnight, and at 12:30pm today the mercury had passed 40C.

At the Australian Open, officials have applied the extreme heat policy for the first time this week with temperatures consistently above 40C since Tuesday.

And temperatures are set to hit 40C in parts of Sydney today.

Canberra is expecting another hot day after Wednesday's maximum of 40.2C nudged the January record set in 1968, falling shy by just 1.2 degrees.

The heatwave is putting a strain on emergency and health services in the affected states, as well as their respective power grids. Total fire bans have been issued for South Australia, Victoria and the ACT.

South Australia and Victoria are braced for near-record temperatures and the spread of bushfires as heatwave conditions persist in south-eastern Australia today.

The states are bearing the brunt of scorching heat and high-fire-danger conditions, while New South Wales and the ACT are also expecting near-record temperatures.

Adelaide, which the Bureau of Meteorology (BoM) confirmed as the hottest city in the world soon after midday, is expected to experience one of its hottest days on record, with a forecast top of 46 degrees Celsius[114.8ºF].

The BOM has confirmed #Adelaide is currently the hottest city in the world at 42.4°C[108.3ºF]. A maximum temp of 46°C is forecast #heatwave — ABC News 24 (@ABCNews24) January 16, 2014

However, much of the fire danger is centred on SA's west coast, where crews are being pushed to the limit as they continue to battle about 15 blazes.

In Victoria, electrical storms overnight sparked blazes across the centre of the state, with one woman hospitalised after being struck by lightning.

Melbourne, meantime, is facing its longest run of 40C[104ºF] days since 1908. It did not drop below 27.2C[81ºF] in the Victorian capital overnight, and at 12:30pm today the mercury had passed 40C.

At the Australian Open, officials have applied the extreme heat policy for the first time this week with temperatures consistently above 40C since Tuesday.

And temperatures are set to hit 40C in parts of Sydney today.

Canberra is expecting another hot day after Wednesday's maximum of 40.2C nudged the January record set in 1968, falling shy by just 1.2 degrees.

The heatwave is putting a strain on emergency and health services in the affected states, as well as their respective power grids. Total fire bans have been issued for South Australia, Victoria and the ACT.